The creation, distribution, and exchange of digital documents has become a commonly accepted alternative to printing documents, both for purposes of efficiency and for environmental purposes, Examples of digital documents that may be created, distributed, or otherwise exchanged include, for instance, electronic word processing documents, electronic spreadsheets, electronic presentations, electronic drawings, portable document format (PDF) files, and web pages, e.g., HTML, CSS, or other web format files. Digital documents may be confidential or highly confidential, and in some cases users may wish to control the distribution of such documents.
Many digital documents have become a mixture, or a composite, of separate parts created in differing file formats. Different parts may be combined together through various serialization mechanisms such as a ZIP archive or TAR archive. One example of a composite document is a business proposal document including product images as JPEG files, a marketing video clip as a MOV file, a PowerPoint presentation as a PPT file, and a financial details spreadsheet as an XLS file. Composite documents may be presented to a user through specialized software as a single editable, browsable, searchable, approvable, or usable document.